F-Tech was first to present a solar powered GPS receiver based on the SiRF StarIII chipset. The technology has developed further and now, F-Tech has introduced a new series of solar powered GPS receivers, smaller in dimensions and using a different chipset from MediaTek. The F-Tech Solar 2.5MR promises superb technology and autonomy. We compare it with a well known SiRF Star III receiver from Globalsat, the BT-338.

- F-Tech Solar 2.5MR

Mini Solar Bluetooth GPS Receiver is a total solution for GPS receivers. High capacity rechargeable lithium-ion battery, GPS antenna, Blue tooth transmit/receive system are included. It is designed on the most advanced chipset solutions, using either the SiRF starIII or MediaTek, providing full-functionality, RoHS compliance, industry-level locating capacity and low prices.

You can use the Mini Solar Bluetooth GPS Receiver as a vehicle navigator, security system, geographic measurement tool, and for agriculture purposes. The Mini Solar Bluetooth GPS Receiver operation requirement is a proper power supply and the open sky-view. This Bluetooth GPS Receiver can communicate with other electronic devices through the Blue-tooth interface. Built-In Flash Memory can save satellite information and do almanac refresh periodically. This will shorten Time To First Fix (TTFF) effectively.

The battery life is much longer than that offered by competitor devices. The Lithium-ion battery can be re-charged under natural or artificial light, regardless of whether the BT2.5 receiver is turned on or off. Most of the time, you will not require a charger! The Mini Solar Bluetooth GPS Receiver is designed for high position accuracy. It will update the satellite position every second. The Mini Solar Bluetooth GPS Receiver auto-locating feature, is capable of automatically determining a navigation solution without intervention.

The new solution from F-Tech uses the MediaTek MT3 GPS chipset. Below we can see a comparison between the MT3 and SiRF Star III chipsets:

Core GPS processor

MediaTek MT3

SiRF Star III

General

Working Frequency

L1, 1575.42MHz

C/A code

1.023 MHz chip rate

Satellite Tracking Count

32 (NEW)

20

Sensitivity

-158dBm

-159dBm

Antenna Type

Active

Passive

Acquiring Position Speed

Cold Start

<37 Sec, average

<41 Sec, average

Warm Start

<36 Sec, average

<37 Sec, average

Hot Start

<1 Sec, average

<1 Sec, average

Reacquisition Time

<1 Sec

0.1 Sec (Typical)

Refresh Rate

Up to 5 Hz

1 Hz

Acquiring Position Accuracy

Position

3m CEP(50%),
without SA (horizontal)

10 meters, 2D RMS

WAAS/EGNOS

<2.5m

7 meters, 2D RMS

Speed

0.1 m/sec

Time

100 ns RMS

1 microsecond
synchronized to GPS time

Acquiring Position Range

Altitude

<18,000m

Speed

<515m/sec

Acceleration

<4G

GPS Protocol

NMEA 0183(V3.01) GGA,GSV,RMC,VTG

Baud Rate

9600,N,8,1

Input Power

5V DC

Power consumption

45 mA average

75 mA average

30 mA with Solar panel

60 mA with Solar panel

Working Environment

Working Temp.

-40°C ~ +85°C

Relative Humidity

5% ~ 95% un-compressed

Looking at the specs, we can see significant differences between the chipsets in terms of sensitivity, cold start time and refresh rate. Both receivers support WAAS/EGNOS, although the MT3 promises much better "position accuracy" (2.5 vs 7.0m) compared with the SiRFStarIII. Another interesting feature is the much lower power consumption, 45mA vs 75mA, and with the Solar panel, the MT3 chipset can stay online for twice as long as the SiRFStarIII.